This sensitive bio-monitoring circuit was found in the December 1984 issue of Radio Electronics magazine. The circuit is powered by a 9 V battery and uses a low-impedance headphone output.
This two-color LED indicator was found in a Popular Electronics from the 90's. The transistor...
This circuit was found in a Radio Electronics from the 90's. It provides lower frequency signals from...
This monostable circuit uses one of the two flip-flops available on the CMOS 4098 integrated...